Michael Adams wrote:
What does the FAA say about adding IFR certification to planes which do not
have it? Can IFR be added to any plane, or does it have to have some sort
of "pre-cerfication" by the manufacturer for make and model? This question
came up, because I have seen IFR added to a few aerobatic models, presumably
for "emergency IFR". I know for helicopters, you can't add IFR unless it
meets certain stability requirements. I wasn't sure about planes.

"adding IFR certification"? please explain...

rats...my copy of the FAR is at the hangar. but if I remember correctly,
the requirements include

static/pitot check every 24 months
mode c transponder
communication equipment adequate to talk with ATC (radio that has .x25)
navigation equipment as appropriate (can't remember the exact minimum but
I think it's 1 VOR receiver and indicator...is ILS required? Possibly
an ADF/DME in addition...)